feature: HL7 FHIR R4 Integration

2026-06-27 22:23:45 +08:00
parent 756cff332c
commit 5646dfddb4
27 changed files with 2658 additions and 16 deletions
@@ -0,0 +1,137 @@
+using Hl7.Fhir.Model;
+using FhirObservation = Hl7.Fhir.Model.Observation;
+
+public static class ObservationMapper
+{
+    private static readonly Dictionary<string, string> LoincToVigilCare = new()
+    {
+        ["8867-4"] = "HEART_RATE",
+        ["8310-5"] = "TEMP_C",
+        ["8480-6"] = "BP_SYSTOLIC",
+        ["8462-4"] = "BP_DIASTOLIC",
+        ["9279-1"] = "RESP_RATE",
+        ["2708-6"] = "SPO2",
+        ["2345-7"] = "GLUCOSE_MG_DL",
+        ["2823-3"] = "POTASSIUM_MEQ_L",
+        ["2951-2"] = "SODIUM_MEQ_L",
+        ["2524-7"] = "LACTATE_MMOL_L",
+        ["6690-2"] = "WBC_K_UL",
+        ["718-7"] = "HEMOGLOBIN_G_DL",
+        ["2160-0"] = "CREATININE_MG_DL",
+    };
+
+    private static readonly HashSet<string> VitalSignCodes =
+    [
+        "HEART_RATE", "TEMP_C", "BP_SYSTOLIC", "BP_DIASTOLIC", "RESP_RATE", "SPO2"
+    ];
+
+    /// <summary>
+    /// Maps a VigilCare Observation entity to a FHIR R4 Observation resource.
+    ///
+    /// Mapping decisions:
+    /// - ObservationCode maps to LOINC codes where a standard mapping exists.
+    ///   Unknown codes use a local CodeSystem with the original code as display.
+    /// - Value + Unit maps to Observation.valueQuantity with UCUM unit codes.
+    /// - RecordedAt maps to effectiveDateTime (when the observation was clinically
+    ///   relevant), not issued (when the system recorded it).
+    /// - Source and SourceBatchId are preserved as extensions for provenance.
+    /// </summary>
+    public static FhirObservation ToFhir(Observation entity, string baseUrl)
+    {
+        var observation = new FhirObservation
+        {
+            Id = entity.Id.ToString(),
+            Meta = new Meta
+            {
+                VersionId = "1",
+                LastUpdated = entity.CreatedAt,
+            },
+            Status = ObservationStatus.Final,
+            Subject = new ResourceReference($"Patient/{entity.PatientId}"),
+            Encounter = new ResourceReference($"Encounter/{entity.EncounterId}"),
+            Effective = new FhirDateTime(entity.RecordedAt),
+            Issued = entity.CreatedAt,
+        };
+
+        observation.Code = MapObservationCode(entity.ObservationCode);
+
+        observation.Value = new Quantity
+        {
+            Value = entity.Value,
+            Unit = entity.Unit,
+            System = "http://unitsofmeasure.org",
+            Code = MapToUcum(entity.Unit),
+        };
+
+        var category = IsVitalSign(entity.ObservationCode) ? "vital-signs" : "laboratory";
+        observation.Category.Add(new CodeableConcept(
+            "http://terminology.hl7.org/CodeSystem/observation-category",
+            category));
+
+        if (!string.IsNullOrEmpty(entity.Note))
+        {
+            observation.Note.Add(new Annotation { Text = new Markdown(entity.Note) });
+        }
+
+        observation.Extension.Add(new Extension(
+            "urn:vigilcare:source",
+            new FhirString(entity.Source)));
+
+        if (entity.SourceBatchId.HasValue)
+        {
+            observation.Extension.Add(new Extension(
+                "urn:vigilcare:source-batch-id",
+                new FhirString(entity.SourceBatchId.Value.ToString())));
+        }
+
+        return observation;
+    }
+
+    /// <summary>
+    /// Reverse LOINC → VigilCare code mapping for FHIR search by LOINC code.
+    /// </summary>
+    public static IReadOnlyDictionary<string, string> GetReverseLoincMapping() => LoincToVigilCare;
+
+    /// <summary>
+    /// VigilCare observation codes that represent vital signs (used for category search).
+    /// </summary>
+    public static IReadOnlyCollection<string> GetVitalSignCodes() => VitalSignCodes;
+
+    private static CodeableConcept MapObservationCode(string code) => code switch
+    {
+        "HEART_RATE"       => Loinc("8867-4", "Heart rate"),
+        "TEMP_C"           => Loinc("8310-5", "Body temperature"),
+        "BP_SYSTOLIC"      => Loinc("8480-6", "Systolic blood pressure"),
+        "BP_DIASTOLIC"     => Loinc("8462-4", "Diastolic blood pressure"),
+        "RESP_RATE"        => Loinc("9279-1", "Respiratory rate"),
+        "SPO2"             => Loinc("2708-6", "Oxygen saturation"),
+        "GLUCOSE_MG_DL"    => Loinc("2345-7", "Glucose [Mass/volume] in Serum or Plasma"),
+        "POTASSIUM_MEQ_L"  => Loinc("2823-3", "Potassium [Moles/volume] in Serum or Plasma"),
+        "SODIUM_MEQ_L"     => Loinc("2951-2", "Sodium [Moles/volume] in Serum or Plasma"),
+        "LACTATE_MMOL_L"   => Loinc("2524-7", "Lactate [Moles/volume] in Serum or Plasma"),
+        "WBC_K_UL"         => Loinc("6690-2", "Leukocytes [#/volume] in Blood"),
+        "HEMOGLOBIN_G_DL"  => Loinc("718-7", "Hemoglobin [Mass/volume] in Blood"),
+        "CREATININE_MG_DL" => Loinc("2160-0", "Creatinine [Mass/volume] in Serum or Plasma"),
+        _ => new CodeableConcept("urn:vigilcare:observation-code", code, code),
+    };
+
+    private static CodeableConcept Loinc(string code, string display) =>
+        new("http://loinc.org", code, display);
+
+    private static string MapToUcum(string unit) => unit switch
+    {
+        "bpm"          => "/min",
+        "C"            => "Cel",
+        "mmHg"         => "mm[Hg]",
+        "breaths/min"  => "/min",
+        "%"            => "%",
+        "mg/dL"        => "mg/dL",
+        "mEq/L"        => "meq/L",
+        "mmol/L"       => "mmol/L",
+        "K/uL"         => "10*3/uL",
+        "g/dL"         => "g/dL",
+        _ => unit,
+    };
+
+    private static bool IsVitalSign(string code) => VitalSignCodes.Contains(code);
+}